Hino FB1817 headlight bulbs utilize H4651 size for high beam and H4656 size for low beam applications. The replacement chart covers vehicle production spanning 1998 to 2004 with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Hino FB1817 uses the H4651 bulb size for its high beam headlight across all listed model years from 1998-2004, with no variation in specification across that span.
The low beam headlight position on the FB1817 uses the H4656 across the same 1998-2004 model year range.
Both the H4651 and H4656 are ANSI-standardized sealed beam units recognized in the US and Canadian markets, meaning they conform to a regulated performance and physical standard rather than a proprietary manufacturer specification.
The 4x6-inch rectangular form factor is a sealed beam housing in which the lens, reflector, and filament are fused into a single glass unit, making the entire assembly the replaceable component rather than an internal bulb.
Because the H4651 and H4656 share the same 4x6-inch rectangular sealed beam format and both operate at 12V, they are physically similar, but they are not interchangeable between the high beam and low beam positions due to differences in their filament and beam pattern configurations.
The sealed beam construction of both units means that any failure of the filament or lens requires replacement of the whole sealed assembly, as no internal components are separately serviceable.
Both units operate on a 12V electrical system, which is the standard for light-duty and medium-duty vehicle electrical architectures in the markets where these ANSI types are specified.